1. Field of the Invention
This invention relates to communication methods and systems for transmission and reception of packets collecting data that are input in a sporadic or discrete manner. In addition, this invention also relates to recording media that store communication programs for transmission and reception of packets collecting sporadically input data.
2. Description of the Related Art
Conventionally, there are provided various systems that collect sporadically or discretely input data into prescribed units called ‘packets’, which are subjected to transmission and reception in accordance with the prescribed sequence of communications. FIG. 6 shows a control flow for use in the existing communication system that is well known. Reference numeral 300 designates a packetizing process of data, wherein a timer is initialized every time data are input thereto (see step 301). In step 302, input data are collected in a buffer. Then, the data collected in the buffer are subjected to collective transmission in step 305 when the buffer is fully occupied by the input data (see step 303) or when a prescribed time period elapses after the time of inputting the last data (see step 304).
If the buffer has vacant space (or remaining capacity), even though the elapsed time counted from the timing of inputting the last data has not reached the prescribed time value, the system is set in a standby state waiting for an input of next data until a prescribed condition is established.
FIG. 7 shows relationships between input and output timings of data along with the same time axis. Reference symbol ‘T’ denotes a time interval for a timeout. The system inputs data D1 to D4 in a sporadic manner, wherein these data are subjected to the foregoing packetizing process to produce two pairs of data, namely a first pair of data D1 and D2 and a second pair of data D3 and D4, which are subjected to transmission as packets. Originally, the data D1 to D4 are mutually separated from each other in time by time intervals t12, t23 and t34. When the transmission unit of the system performs transmission of the aforementioned packets, it disregards time information representing the aforementioned time intervals. In the reception unit of the system, the packets are subjected to reproduction in such a manner that the original data D1 to D4 are mutually separated from each other in time by time intervals t12′, t23′ and t34′. That is, due to the transmission and reception, the original time intervals t12-t34 between the data D1-D4 are changed to the time intervals t12′-t34′. If data Dn (where n=1 to 4) represent performance information of a musical instrument such as MIDI data (where ‘MIDI’ indicates the standard for Musical Instrument Digital Interface), the conventional system cannot accurately reproduce the original time information representing mutual time intervals of data. This causes various problems in reproduction of musical information. In particular, the conventional system bears the problem that dispersions or deviations are likely to occur in delays of data due to data processing during transmission.